I've been thinking again, for no very compelling reason, about the merger of the two great Chicago exchanges in 2007. In form, it was an acquisition of the Chicago Board of Trade by the Chicago Mercantile Exchange, after the CME won a bidding war with the Intercontinental Exchange (ICE), I'm looking at Erika Olson's book about the behind-the-scenes maneuvering that ended in that result. One of the many subplots involves ERPs, the "exercise right privileges" possessed by many CBOT members with regard to yet another Chicago institution, the Chicago Board Options Exchange. This takes some explaining. First, neither the CBOT nor the CBOE is a mere set of initials. Each is a true acronym, "see-bot" and "see-bow" respectively. Second, the CBOE, established in 1973, does what the name implies. It provides a forum for the trade in options. It was initially a spin-off from the CBOT, and they had a close continuing relationship. One part of that: ever...